Slideshow
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Figure 1. Lateral radiograph of the thoracic spine before kyphoplasty.
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Figure 2. Lateral radiograph of the thoracic spine 2 weeks after kyphoplasty.
A 90-year-old woman presents to the office 2 weeks after undergoing kyphoplasty for the treatment of vertebral compression at T12. The patient reports increasing mid-back pain and difficulty ambulating. She denies any bowel or bladder changes. Figure 1 shows a lateral radiograph of the thoracic spine before kyphoplasty and Figure 2 shows a lateral radiograph at the current office visit. On physical examination she has pain over the lower thoracic spine to palpation.
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Kyphoplasty involves the injection of polymethylmethacrylate cement into the compressed vertebral body to help restore vertebral height. As a result, the treated vertebral body becomes stiffer than the adjacent, untreated levels. The stiffness of the cement increases the load on adjacent vertebral bodies, which increases the likelihood of an adjacent vertebral fracture. For this reason, there is concern that adjacent level fractures are more likely to occur after kyphoplasty.1,2
However, whether an adjacent level fracture occurs as a result of a kyphoplasty or whether the adjacent level fracture would have occurred regardless of kyphoplasty remains unclear. Fribourg et al found that adjacent level fractures are most likely to occur within 2 months of kyphoplasty.1 Remodeling of adjacent level endplates after kyphoplasty is thought to decrease the rate of fracture after 2 months. Fribourg et al found that 21% of patients had an adjacent level fracture within 2 months of a kyphoplasty.1
Movrin found that the risk of an adjacent vertebral level fracture within 1 year of kyphoplasty is between 6.5% and 16.4%, while the risk of a symptomatic adjacent level fracture in elderly patients not treated with kyphoplasty is approximately 5% within 1 year. Patients at the highest risk of adjacent level fracture include those with advanced osteoporosis and increased focal kypohosis.2
The patient sustained an adjacent vertebral fracture at the T11 level 2 weeks after her kyphoplasty at T12.
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopaedics for Physician Assistants.
References
1. Fribourg D, Tang C, Sra P, Delamarter R, Bae H. Incidence of subsequent vertebral fracture after kyphoplasty. Spine. 2004;29(20):2270-2276. doi:10.1097/01.brs.0000142469.41565.2a
2. Movrin I. Adjacent level fracture after osteoporotic vertebral compression fracture: a nonrandomized prospective study comparing balloon kyphoplasty with conservative therapy. Wien Klin Wochenschr. 2012;124(9):304-311. doi:10.1007/s00508-012-0167-4
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